Electropneumatic brake



l March 29, 1927. c, FARMER ET A'- ...JECTROPNEUMATIC BRAKE mea May 27,i926 Patented Mar'. 29, (1)927.

. UNITED' STATES PATENT OFFICE.

emma o. ranura, or rrrrsnunen, bANnJosnmrc. noo-UNE, on nnenwoon,rmsYLvANIA, AssIGNoBs To THE wEsrINGnoUsE am BRAKE contraluz, or wn;-

HEVBDING, PENNSYLVNIA, A.' CORPORATION 0F PENNSYLVANIA.

" ELECTBOPN-EUMATIC BRAKE.

Application nled lay 87, 1926.. Serial No. 111,995.

This invention relates to safetycar control equipments', and theprincipal object of our invention is to provide an im roved ands1mplified electro-pneumatic sa ety car control 5 equipment.

In the accompanying drawing, the single ligure is a diagrammatlc view ofa safetycar control equipment embodying our invention.

` As shown in the drawing, the e uipinent l .may comprise a. brakeswitch, at eac end ofthe car havin the'operating positions designated asre ease, lap, and service, and a foot controlled switch device at eachend of the car comprising a push button 1 and a l switch member 2adapted to 'be operated by said button.

The equipment also includes an emergencyv valve device`3, a brakecylinder 4, a main res-v ervoir 5, a release magnet 6, a service magnet7, an emergency magnet 8, a cut-oli switch switch device 10.

The emergency valve device 3 comprises a casing havinga piston chamber11I connected to a control pipe 12 and containing a piston 13 and a.valve chamber 14 connected to the main reservoir 5 through pipe 15 andcontaininga slide valve 16 adapted to be operated by 'piston 13. l t Indperation,.with -the push butto'n l held depressed, the switch member 2closes a cir'. cuit from a current supply wire 17 to a wire v18 which isconnected to the emergency mag# l net 8. Said `magnet is therebyenergized 'and operates double beat valves 19 `and 20, so that valve 19is seated, cuttingoif communication from control pipe 12 to anatmospheric exhaust port 21, and valve 20 is unseated, permitting Huidunder pressure to be supplied fromn the main` reservoir pipe- 15,through` a restricted port 22, tothe control pipe 12. Pgistonchamber 11being thus charged witli fluid at main reservoir pressure andthevalve-chamber 14 being connected to the main reservoir, the piston 13will be shifted to normal release position, due to the diiierentialimpressure which is createdby the small piston 23 being donstantlysubject to atmospheric pressure. With 'the .brake switch inu releaseposition, the current supply wire 17 is connected to devicev 9, and a,holding coill controlling unseated and il id under wire 24, which leadsto release magnet `6, so

that said magnet is energized and operates to'hold the release valve 25unseated. The

ap lication magnet 7 is deener ized, and the va ve 26 is thereforepermitte to seat. The

releasevalve 25 being o en, the brake'cylinder 4 is connected to teexhaust, through pipe27, passage. 28, cavity 29 in emergency ,Slidevalve 16, passage '30, pipe 31, and past valve 25 to eghaust port 32.

The cut-oil switch device 9 comprises a cas- 1 in containing a piston33, connected on one., si e to a pipe 34, leading to pipe 31 and saidpiston is providedvwith a stem 35 Vcarrying a contact member 36adapted'to controla circharged with fluid under pressure, the piston 38is forced to its upper position,' in

which the switch member 40 closes a circuit,

to a holding coil (not shown) which maintains the powercircuit. y j

' An application of the brakes may be effect-y ed by moving the brakeswitch to service zipbrake cylinder,-

plication position, in which the fcurrent supply wire 17 is connected towire 41, which leads to the applicationmagnet 7. Said magnet being thusenergized, the valve 26 is ressure is vented from one side of al relayvalve 42 through passage 43, past valve 26 to .passage 44,

which is open to the brake cylinder 4. The relay valve'42` is thenmovedupwardly byv fluid at main reservoir pressure acting on the outerlower area of said-valve and there by the mainl reservoir pipe 45 isconnected to passage 44; so that fluid from the main reservoir issupplied to the brake cylinder through pipe 31, cavity 29 in slidevalve.16, passage 28, and pipe 27. The release vmagnet 6 is deenergized 1n theservice application popressure be increased to a predetermined sition ofthe brake switch, so'that the valve 25 is permitted to seat and preventthe esca e of liuid from the brake cylinder.

llVhen `a. service application of the brakes is effected, iuid underpressure is supplied from the pipe 31, throu h pipe 34 to cut-oft'switch piston 33, and i? the brake cylinder amount, said piston will beshifted upwardly to cause the switch member 36 to close a circuit fromsupply wire 17 to emergency magnet wire 18.

'It will thus be evident, that if a service application of the brakes iseffected, the foot button 1 may be released without causing theemergency magnet 8 to be deenergized. i

If the brakes are not applied and the motornian should release the footbutton 1, either accidentally or by design, the circuit of the emergencymagnet 8 will be opened, permitting the double beat valve 2O to seat andthe valve 19 to unseat. The unseating of valve 19 permits fluid underpressure from the control pipe 12 to be-vented to the exhaust port 21and the reduction in control pipe pressure thus produced, causes theemergency piston 13 to be shifted to its outter position by fluid underpressure in valve chamber .14. The slide valve 16 is thus moved toemergency position,in which passage 28 is opened to valve chamber 14,permitting fluidunder pressure to flow from said,7 valve chamber andconsequently the main reservoir 5 to the brake cylinder 4, so as tocause an emergency application of the brakes. u

The venting of fluid from the control pipe 12 also reduces the pressureon piston 38, permitting spring 46 to shift the piston 38 to its lowerposition and thereby causing the switch member 40 to open the circuit ofthe holding coil. The holding coil being thus deenergized, the powercircuit is opened.

. The brakes may be released after an emergency application of thebrakes, by depressing the foot button .1, `whereby the emergency magnet8 is again energized, so as to effect the closure of valve 19 and theopening of valve 20'.' Fluid-under pressure is then supplied from themain reservoir to the control pipe 12 and the emergency piston 13 isreturned to release' position, in which the brake cylinder 4 isconnected to the atmosphere, as hereinbefore explained.

The piston 38 is also moved upwardly by fluid under pressure in thecontrol pipe 12, so as to close the circuit to the holding coil and thuseffect the closing of the power circuit.

When the motorman goes from one end of the car to theother, he canprevent an emergency application of'the brakesupon release of the pushbutton 1, if he makes ,a service application of the brakes of apredetermined amount, and when he is at the other end of the car he canrelease the brakes by pressing down the push button 1, so as to closethe circuit to the emergency magnet 8 and by moving the brake switch torelease position. The brakes will then be released, as hereinbeforedescribed.

A conductors valve 47 connected to' the control ipe 12 may be installedin the cab, so that t e motorinan may operate said valve to vent airfrom the control pipe to eiiect an emergency application of the brakes,in case of possible failure of the electric control. A similarconductors" valve 48,1 may be provided for control by the conductor, incase the conductor or a passenger should find it necessary to effect anemergency application of the brakes.

Having now described our invention, what we claim as new and desire tosecure by Letters Patent, is

1. In a safety control equipment, the combination withv a control pipeand an emergency valve device operated upon a reduction in fluidpressure in said pipe for effecting an application of the brakes, of avalve for ventin fluid from said pipe, a magnet for operating saidvalve, a foot controlled switch for controlling the circuit of saidmagnet, and a switch device operated upon an a plicatiton of the brakesforl controlling the circuit ofisaid magnet.

2. In a safety control equipment, the combination with a control pipeand an einergency valve device operated upon a reduction in fluidpressure in said pipe for effecting an application of the brakes, of avalve for venting fluid from said pipe, a magnet adapted upondeenergization to open said valve, a foot cntrolledswitch operative uponrelease for opening the circuit of said magnet, and a switch deviceoperated upon fapplying thebrakes for closing'the circuit to saidmagnet.

3. In a safety control equipment, the combination witha control pipe andan einergency valve device operated upon a ,reduction in fluid pressurein said pipe for effecting an application of the brakes, of a valve forventin Huid from said pipe, a valve for supplying fluid under pressureto said pipe, and a magnet for operating said valves. j

. 4. y In a safety control equipment, the combination with 'a brakecylinder, a control pi e, and a valve device operated upon a reductionin iluid pressure in said pipe for effecting an emergency application ofthe brakes, of a valve for ventin fluid from the control pipe, a magneta apted' upon deener ization for opening said valve, and a switc deviceoperated upon a predetermined increase in pressure in the brakecylyinder for closing'a'circuit to energize said magnet.

5. In a safety control equipment, the combination with electricallycontrolled means for controlling the application of the brakes and abrake switch device for controlling 5 said means, of a control pipe,means operated upon a reduction in pressure in said pipe for effectingan emergency application of the brakes, a valve for venting fluid fromsaid pi a magnet for operating said valve,

and a I oot controlled switch for controlling l0v the circuit of saidmagnet. p

In testimony whereof :we have hereunto set our hands. l v

` CLYDE c. FARMER.

JOSEPH c. MCCUNE.

